Could mass tree planting create flood resilience in this coastal city?
Beira is the capital and largest city of Sofala Province, in Mozambique, and is where the Pungwe River meets the Indian Ocean and Mozambique Channel, in the central region of Mozambique. The Mozambique Channel is prone to hurricanes, but with climate change, it is highly likely that these events could become more frequent and more damaging. Around the city of Beira, also at sea-level, the residential and port areas were inundated with river flood waters and storm surges flowing in from the sea, and were largely destroyed. Mangroves could be replanted, and it is well known that replanting mangrove areas is a good disaster management initiative. In Beira, the coastal mangrove areas have largely been removed, as they have been in many other parts of the world. Had they remained in place, they would have provided a first level of defence against coastal surges. They can be replanted.
In the case of Mozambique’s flat coastal plain, a project to plant trees and undertaken a landscape-scale flood intervention, would be designed with stakeholders to control flood waters and storm surges, as well as create other social benefits. Most of eastern Mozambique is a flat coastal plain at the same elevation as sea level, and is highly vulnerable to flooding, whether from the sea or from river flood waters. Residents of this area are mostly subsistence farmers on small plots of land, and who have no insurance or safety nets, other than keeping some of their see for next season’s planting. Cyclone Idai robbed them of their crops, their planting seed, their livestock and their homes. Clearly, a severe situation, and one which will become a regular occurrence.
It might be time to conduct a feasibility study for a ‘Great Strong Wall of Trees for Beira’, essentially developing a well-thought out mass tree planting programme, designed for flood and storm surge disaster management in the landscape around Beira. This scheme could be modeled on the Great Green Wall for Africa, and other urban tree planting schemes, in the way the project is phased and monitored. Important elements to consider would be how such project is researched, set up, funded and managed. Also, the tree species component of impacted catchments needs to be cataloged for replanting. The easiest way to get forests to regenerate is to keep goats out of areas with fencing. The seed banks in the soil can then germinate and grow, and in this way the ‘trees plant themselves’.
Some issues to consider are whether inland tree plantings can help to stabilise inland river banks, or even help to raise river banks over time to contain flood waters. Such a project would need to be established in collaboration with forestry experts and other organisations, professionals and taking note of lessons learned by other coastal cities that are engaging with remedial tree planting at scale. Expect benefits in 20 years time, if such a project started right now! In other words, this is no quick fix.